Problem:

When issuing a rebuild command of this form:

 rebuild infile,outfile -t:MF8

The error appears:

REBUILD aborted - File type requires use of o option

Resolution:

This error appears when the input file is not an indexed file, for example, when the input file is a sequential or relative file.  The purpose of a rebuild command with this general syntax:

 rebuild infile,outfile -t:MF8

is to convert an indexed file into IDXFORMAT"8" format, which is often done to facilitate large file support for indexed files.

If the file in question is a line sequential, record sequential, or relative file, and is one of the files you are concerned might grow larger than 1 gig for shared access, or 4 gig for exclusive access, then refer to this knowledgebase article:

http://community.microfocus.com/microfocus/mainframe_solutions/enterprise_server/w/knowledge_base/17683.file-size-limits-for-server-express-and-net-express.aspx

wherein it explains that a person can specify the FILEMAXSIZE=8 file handler configuration option, to allow line sequential, record sequential, and relative files to grow as large as 4 exbibytes for shared access or 8 exbibytes for exclusive access.  Line sequential, record sequential, or relative files do not need to be rebuilt into IDXFORMAT"8" indexed files for the purpose of large file support; they just need the FILEMAXSIZE=8 file handler configuration option to be set.